【洛天依】Luo Tianyi - You Owe Me a Hug 欠一个拥抱 (English Subbed)
I like how on the original video, besides chinese, there's subtitles of at least four other languages in the comments.
lyrics, composer & arrangement: 潜移默化P
illustrator: Chenny0_0
PV: BOBE(EMO.C)
Original: http://www.bilibili.tv/video/av343513/
Uploader's comment:
话说这首歌是天依在整理绫的遗物时，发现绫有一首未完成的歌，所以歌词前段部分是绫写的，后面是天依补上的。
TL:
When Tianyi was tidying Ling's things, she found a half-finished song that Ling wrote, so the first part of the song is written by Ling and the rest was added by Tianyi.
(Ling of course refers to Yuezheng Ling)